The present invention relates in general to coated glass, and specifically to perfluoroalkoxy copolymer coated glass, tetrafluoroethylene perfluoromethyl vinyl ether copolymer coated glass, a method of manufacturing perfluoroalkoxy copolymer coated glass and a method of manufacturing tetrafluoroethylene perfluoromethyl vinyl ether copolymer coated glass.
Coatings have been applied to glass to change one or more characteristics of the glass. One such coating is perfluoroalkoxy copolymer (“PFA”) which is one of the compounds sold by E.I. Du Pont de Nemours and Company under the trademark Teflon®. PFA is most commonly used as a non-stick coating on cookware such as pots and pans. PFA has also been used to coat glass such as automobile windshields and light bulbs.
The structure of PFA makes it highly resistive to sticking or adhering to other substances. In particular, the structure of perfluoroalkoxy copolymer is a copolymer of tetrafluoroethylene (CF2=CF2) with a perfluoroalkoxy vinyl ether [F(CF2)mCF20CF—CF2]. The resultant polymer contains the carbon-fluorine backbone chain typical of polytetrafluoroethylene with perfluoroalkoxy side chains. The side chains are connected to the carbon-fluorine backbone of the polymer through flexible oxygen linkages. The fluorine atoms in the chain resist almost any other atom or molecule, even other fluorine atoms. As a result, the fluorine atoms in PFA resist adhering to or even being near other molecules. Thus, molecules at the surface of PFA repel the other molecules and almost anything else that attempts to adhere or come close to the PFA molecule. Additionally, the bond between the carbon and fluorine atoms is extremely strong. The bond is so stable that little to almost nothing will react with it. Thus, PFA is a desirable coating to coat glass products because it is a material, which minimally reacts with other compounds. PFA also includes very strong bonds between its atoms which enables the coating to withstand extreme temperature and pressure conditions.
Another such coating is tetrafluoroethylene perfluoromethyl vinyl ether copolymer (MFA). MFA, sold by Solvay Solexis under the trademark Hyflon® is a copolymer of tetrafluoroethylene (CF2=CF2) with a perfluoromethyl vinyl ether [CF2=CF—OCF3]. The chemical composition of MFA provides increased resistance to chemicals, good permeation characteristics and very high stress cracking resistance. Similar to PFA, MFA is highly resistive to sticking or adhering to other substances. Additionally, MFA's increased optical translucency or transparency and reduced haze make it particularly suitable for coating of light bulbs. Thus, MFA is a desirable coating to coat glass products because it is a material, which minimally reacts with other compounds. MFA also includes very strong bonds between its atoms which enables the coating to withstand extreme temperature and pressure conditions.
Another such coating is polyethylene polymer (PE). The chemical composition of PE is a chain of carbon atoms with two hydrogen attached to each carbon atom ([CH2═CH2]n). Additionally, in branched or low-density polyethylene, one or more of the carbon atoms, instead of having hydrogens attached to them, will have another chain of PE attached to them. The chemical composition of PE provides for increased resistance to chemicals, good permeation and very high stress cracking resistance characteristics. PE is a low cost coating that is impact, abrasion and chemical resistant. PE is translucent to opaque, very flexible and non-reactive at temperatures from −50° C. to 80° C. Thus, PE is a desirable coating to coat glass products because it is a material, which minimally reacts with other compounds.
However, there are certain problems with known PFA, MFA or PE coated glass. One known problem is that although the PFA, MFA or PE coats the glass, it does not form a strong bond with or strongly adhere to the glass because of its highly resistive nature with respect to other molecules. Thus, when a glass substrate or glass product coated with PFA, MFA or PE shatters or breaks, certain of the glass shards or pieces break away from the PFA, MFA or PE coating. In some coated glass products such as coated light bulbs, the PFA, MFA or PE coating is applied to the outside of the light bulb. When the light bulb coated with PFA, MFA or PE breaks, the glass pieces remain inside the light bulb because the PFA, MFA or PE layer creates a closed container such that the glass pieces are contained inside the light bulb. However, other glass products such as laboratory beakers are open glass containers. Therefore, the glass shards in these products can become loose and break away from the surfaces of these products. The glass shards are unsafe and may cause injury or severe injuries to users of these glass products.
Accordingly, there is a need for glass-coated materials and glass products that are coated with a material that has a very high bond strength and which strongly adheres to glass. Additionally, there is a need for a glass-coated materials and products that maintain the structural integrity of the surfaces of the glass materials and products.